Heat exchangers used to cool and heat blood or solution for cardioplegia (techniques for reducing the risk of damage to the heart by cooling and administering drugs to the heart) have included inlet and outlet fittings for both the heat-exchanging fluid or coolant (e.g., water) and the blood or cardioplegia solution, and suitable tubing for supplying or removing the fluids has been separately connected to each fitting. Typically, the fittings for tubing carrying the heat-exchanging fluid are of the quick-disconnect type, such as sold under the trade designation "Hansen Fittings" by The Hansen Manufacturing Co. of Cleveland, Ohio, wherein a sleeve adjacent one end of the tubing presses ball bearings held in the end of the tubing radially inwardly into an annular channel in the male portion of the fitting on the heat exchanger, thereby securing the tubing to the heat exchanger. The sleeve is movable axially with respect to the tubing to allow the ball bearings to move radially outwardly from the channel, thereby releasing the male portion of the fitting so that the tubing may be separated from the heat exchanger. The fittings are relatively large and heavy compared to the size of modern heat exchangers, and must be individually connected and disconnected to the heat exchanger. The fittings do not ordinarily hold the heat exchanger in a suitable position for use so that the heat exchanger must be separately clamped to a support stand, and the weight of the fittings increases the difficulty of supporting the heat exchanger.